Fate of urea nitrogen applied to a banana crop in the wet tropics of Queensland

This paper reports a study in the wet tropics of Queensland on the fate of urea applied to a dry or wet soil surface under banana plants. The transformations of urea were followed in cylindrical microplots (10.3 cm diameter x 23 cm long), a nitrogen (N) balance was conducted in macroplots (3.85 m x 2.0 m) with N-15 labelled urea, and ammonia volatilization was determined with a mass balance micrometeorological method. Most of the urea was hydrolysed within 4 days irrespective of whether the urea was applied onto dry or wet soil. The nitrification rate was slow at the beginning when the soil was dry, but increased greatly after small amounts of rain; in the 9 days after rain 20% of the N applied was converted to nitrate. In the 40 days between urea application and harvesting, the macroplots the banana plants absorbed only 15% of the applied N; at harvest the largest amounts were found in the leaves (3.4%), pseudostem (3.3%) and fruit (2.8%). Only 1% of the applied N was present in the roots. Sixty percent of the applied N was recovered in the soil and 25% was lost from the plant-soil system by either ammonia volatilization, leaching or denitrification. Direct measurements of ammonia volatilization showed that when urea was applied to dry soil, and only small amounts of rain were received, little ammonia was lost (3.2% of applied N). In contrast, when urea was applied onto wet soil, urea hydrolysis occurred immediately, ammonia was volatilized on day zero, and 17.2% of the applied N was lost by the ninth day after that application. In the latter study, although rain fell every day, the extensive canopy of banana plants reduced the rainfall reaching the fertilized area under the bananas to less than half. Thus even though 90 mm of rain fell during the volatilization study, the fertilized area did not receive sufficient water to wash the urea into the soil and prevent ammonia loss. Losses by leaching and denitrification combined amounted to 5% of the applied N.

Laboratory evaluation of two native fishes from tropical North Queensland as biological control agents of subterranean Aedes aegypti

The ability of 2 freshwater fishes, eastern rainbow fish Melanotaenia splendida splendida and fly-specked hardyhead Craterocephalus stercusmuscarum stercusmuscarum. native to North Queensland to prey on immature Aedes aegypti was evaluated under laboratory conditions. The predation efficiency of the 2 species was compared to the exotic guppy, Poecilia reticulata, which is commonly used as a biological control agent of mosquito larvae. Of the 3 fish species tested, M. s. splendida was shown to be the most promising agent for the biological control of Ae. aegypti that breed in wells. Melanotaenia s. splendida consumed significantly greater numbers of immature Ae. aegypti than P. reticulata, irrespective of developmental stage or light conditions. Unlike C. s. stercusmuscarum, M, s. splendida could be handled, transported, and kept in captivity for extended periods with negligible mortality. However, M. s. splendida was also an efficient predator of Litoria caerulea tadpoles, a species of native frog found in wells during the dry season. This result may limit the usefulness of M. s. splendida as a biological control agent of well-breeding Ae. aegypti and suggests that predacious copepods, Mesocyclops spp., are more suitable. However, the use of M. s. splendida as a mosquito control agent in containers that are unlikely to support frog populations (e.g., aquaculture tanks and drinking troughs) should be given serious consideration.

Stability of nest range, home range and movement of the northern bettong (Bettongia tropica) following moderate-intensity fire in a tropical woodland, north-eastern Queensland

Nest use, home-range characteristics and nightly movements by the northern bettong (Bettongia tropica) were examined before and after a low- to moderate-intensity fire in sclerophyll woodland in north-eastern Australia using radio-telemetry. In all, 23 animals were radio-tracked at three-month intervals between February 1995 and May 1996. During November 1995 a low- intensity experimental fire burned the entire home range of most animals. The northern bettong appeared fairly catholic in choice of nest site, with a variety of nest locations and nesting materials used. Prior to the fire, nests were generally located in areas of dense cover, such as the skirts of grass trees (46%) or grass close to a log (29%). After fire removed most ground cover in the nesting areas of most animals, bettongs used remaining shelter such as boulder piles (45%), recently fallen trees (8%) and patches of unburnt vegetation (21%). Nest areas (10.1 ha) of males were significantly larger than those of females (5.4 ha). Home ranges of both sexes were large (59 ha) and most ranges lacked distinct core areas, suggesting that bettongs used all parts of their home ranges equally. High mean rates of nightly movement by the northern bettong indicated that large distances were moved within home ranges during nightly foraging. No significant fire-related changes were detected in home-range size, home-range location, nest-area location or mean rates of nightly movement, suggesting that the northern bettong is well adapted to the low- and medium-intensity fires that characterise its habitat.

Realtime fetal ultrasound by telemedicine in Queensland. A successful venture?

We have established a realtime fetal tele-ultrasound consultation service in Queensland, which has been integrated into our routine clinical practice, The service, which uses ISDN transmission at 384 kbit/s, allows patients in Townsville to be examined by subspecialists in Brisbane, 1500 km away. For the 90 tele-ultrasound consultations performed for the first 71 patients, 90% of the babies have been delivered, and outcome data have been received on all the pregnancies. All significant anomalies and diagnoses have been confirmed. The referring clinicians would have physically referred 24 of the 71 patients to Brisbane in the absence of telemedicine. A crude cost-benefit calculation suggests that the tele-ultrasound service resulted in a net saving of A$6340, and at the same time enabled almost four times the number of consultations to be carried out.

Primary fallopian tube carcinoma: the Queensland experience

The purpose of this study was to review the experience with fallopian tube carcinoma in Queensland and to compare it with previously published data. Thirty-six patients with primary fallopian tube carcinoma treated at the Queensland Gynaecological Cancer Center from 1988 to 1999 were reviewed in a retrospective clinicopathologic study. All patients had primary surgery and 31/36 received chemotherapy postoperatively. Abnormal vaginal bleeding (15/36) and abdominal pain (14/36) were the most common presenting symptoms at the time of diagnosis. Median follow-up was 70.3 months and the median overall survival was 68.1 months. Surgical stage I disease (P = 0.02) and the absence of residual tumor after operation (P = 0.03) were the only factors associated with improved survival. Twenty of the 36 patients (55%) presented with stage I disease and survival was 62.7% at 5 years. No patient with postoperative residual tumor survived. The majority of the patients with fallopian tube carcinoma present with stage I disease at diagnosis, but their survival probability is low compared with that of other early stage gynecological malignancies. If primary surgical debulking cannot achieve macroscopic tumor clearence, the chance of survival is extremely low.

Economic Instruments and Regulatory Approaches in Implementing Riparian Revegetation Options: Observations of the Queensland System

Riparian vegetation can be an effective measure for preventing degradation of streambanks and riparian areas. However, riparian revegetation imposes large costs on landholders associated with tree establishment and removal of land from cropping, while providing benefits to downstream landholders, fishers, the local community and environmentalists. Appropriate policy instruments are required to promote sustainable and balanced use of riparian zones. This article analyses the capacity of existing legislation and other instruments to promote restoration of degraded riparian zones on private land. The role of legislation. economic instruments, community engagement and extension programs, in persuading landholders to revegetate riparian areas and improve riparian vegetation cover; is examined in the context ofa small degraded catchment in an intensive farming area in tropical north Queensland. It is found that while legislation and regulations can control undesirable modification of riparian areas, in general they are unable to make a useful contribution to restoration of these areas; incentives and assistance measures appear to offer greater potential.

A survey of dental and oral trauma in south-east Queensland during 1998

Background: This project investigated the aetiology of dental and oral trauma in a population in southeast Queensland. The literature shows there is a lack of dental trauma studies which are representative of the general Australian population. Method: Twelve suburbs in the south-east district of Queensland were randomly selected according to population density in these suburbs for each 25th percentile. All dental clinics in these suburbs were eligible to participate. Patients presenting with dental and oral trauma were eligible to participate. Results: A total of 197 patients presented with dental/oral trauma over a 12 month period. The age of patients ranged from 1-64 years whilst the most frequently presenting age group was 6-10 years. There was a total of 363 injured teeth with an average of 1.8 injured teeth per patient. Males significantly outnumbered females in the incidence of trauma. Conclusions: The highest frequency of trauma occurred in the 6-10 year age group. Most injuries in this group occurred while playing or riding bicycles. In the next most prevalent trauma group, 16-20 years, trauma occurred as a result of fighting and playing sport. Overall, males significantly outnumbered females by approximately 1.8:1.0. The majority of injuries in the deciduous dentition were to periodontal tissues. In the secondary dentition most injuries were to hard dental tissue and pulp.

A heated air quarantine disinfestation treatment against Queensland fruit fly (Diptera: Tephritidae) for tomatoes

A circulated heated-air treatment at 92% RH to achieve and maintain a minimum fruit core temperature of 44°C for 2 h is shown to disinfest tomatoes against Queensland fruit fly, Bactrocera tryoni (Froggatt) for market access quarantine purposes. The efficacy of the treatment exceeded 99.99%, tested at the 95% confidence level. An estimated 78 439 eggs were used for large-scale trials, as the stage of the pest most tolerant of heat at the treatment temperature.